Apparatus and method for cooling aircraft



Oct. 3, 1950 w. F MAYER APPARATUS AND METHOD FOR COOLING AIRCRAFT 3Sheets-Sheet 1 Filed Dec. 3, 1946 INVENTOR. WALDEMAR F. MAYER ATTORNEY IOct. 3, 1950 w. F. MAYER 2,524,065

APPARATUS AND METHOD FoR COOLING AIRCRAFT Filed Dec. 3,' 194e ssheets-sheet 2 INVENTOR. V wALDEMAR F. MAYER l Oct. 3, 1950 w. F. MAYER2,524,065

APPARATUS AND METHOD FOR COOLING AIRCRAFT Filed Dec. 3, 1946 3Sheets-Sheet 3 INVENTOR. WALDEMAR F. MAYER ATTO R N EY Patented Oct. 3,1950 APPARATUS AND METHOD FOR COOLING AIRCRAFT Waldemar F. Mayer, LosAngeles, Calif., assignor to The Garrett Corporation, Los Angeles,Calif., a corporation of California Application December 3, 1946, SerialNo. 713,881

31 claims. l

a simple and efficient system for cooling the pressurized air which isto be fed to a cabin, wherein an eiiicient cooling effect isaccomplished without the use of commercial refrigerants, but insteademploying air as a coolant and utilizing the cooling eii'ect of an airdriven engine, such as an air turbine.

It is an object of the invention to provide a cooling system and methodwherein compressed air to be cooled and coolant air are passed in heatexchange relation, wherein power recovery engines, such as air turbines,are employed in the paths of ow of the compressed air and/'or of thecoolant air to produce a cooling effect. there being means whereby thepower recovered from the compressed and coolant air is utilized to applya motivating force to the coolant air.

ambient atmosphere externally of the aircraft cabin. In this form of theinvention power is recovered from the compressed air in the aircraftcabin, and the low temperature of the air from the aircraft cabin, afterit has passed through the coolant air turbine, is employed to advantagein cooling the compressed air which is to be cooled and delivered to thecabin.

A further object of the invention is to provide a system and method ofthe character described in the preceding paragraph in which the powerrecovered from the compressed and coolant air is utilized to operate arecirculating fan, generator, oil pump, fuel pump, vacuum pump or otherwork absorbing means. k

It is characteristic of iiuids, such as the gases or compressible fluidemployed in the present invention, that flowing thereof is accomplishedby differential pressure. It is an object of the invention to utilizethis characteristic to accomplish in a cooling device employing acompressible fluid as a coolant, an economical cooling effect byextracting work from the coolant fluid by mechanical means, such as afluid driven engine or turbine, before it contacts and/ or flows overthe heat exchange walls of the cooling device, thereby increasing theefciency of the coolant by lowering its temperature before it extractsheat from the heat exchange walls of the cooling device.

It is a further object of the invention to provide a cooling device ofthe character set forth in the preceding paragraph wherein workextracted from the coolant uid of compressible character is utilized toproduce a suction effect upon the coolant downstream from the heatexchange walls of the cooling device, thereby further increasing thecooling effect of the coolant and by useful employment thereof,recovering the work which has been extracted from the coolant upstreamfrom the heat exchange walls.

A further object of the invention is to. provide a system and method ofthis character wherein coolant air is moved through the coolant passagesof the cooling device by suction effect applied to the outlet of thecoolant passages, thereby producing a reduction in the temperature ofthe coolant as the result of the reduction in pressure caused by thesuction.

Further objects and advantages of the invention may be brought out inthe following part of the specification, wherein specific description isfor the purpose of presenting a full and complete disclosure withoutlimiting the scope of the invention defined in the appended claims.

Referring to the drawings which are for illustrative purposes only,

Fig. l is a partly sectioned view, schematic in character, showing apreferred form of my in vention.

Fig. 2 is a partly sectioned view, schematic in character, showing amodified form of the invention, wherein the compressed air is passedthrough primary and secondary coolers.

Fig. 3 is a, partly sectioned view, schematic in character, showing afurther modified form of the invention.

In the form of the invention disclosed in Fig. 1 a heat exchanger Ill isprovided which may be of any known type of construction having passagesfor the air to be cooled and passages for the coolant air in heatexchange relation in order that the coolant air may absorb heat from aflow of compressed air which is to be cooled and then delivered to thecabin. Within the meaning of the term cabin I include any compartmentinto which the conditioned air is delivered. The heat exchanger has ammnrpggpa with a cooling and power recovery engine comprising a turbineI1 having a rotor I8 fixed on a shaft I9. Connected to one end of theshaft Il is the rotor 23 of a cooling and power 1ecovery engineAdisclosed as a turbine 2I situated in the duct member I5 of the coolantinlet I3.

The pumping device 22, connected to the opposite end of the shaft I9,augments the iiow of the coolant air in the inlet I3 and reduces thepressure on the discharge side of the turbine 2i, thereby increasing thedifferential pressure which would exist between the coolant air on theinlet side of the turbine and the coolant air on the discharge side ofthe turbine if the flow of the coolant air were not augmented by thepumping device 22. This increased pressure differential across thecoolant air turbine 2I increases the cooling effect of the turbine. Thepumping device 22 constitutes a power utilizing means for usefullyapplying a load to the turbine rotors Il and 20 and is shown as acentrifugal suction pump or blower having an'impeller 24 fixed on theshaft I9 so that it will receive rotation from the rotor I8 of theturbine I1 and the rotor 20 of the turbine 2I. The impeller 24 draws airfrom the duct member I8 and discharges the same through an outlet 25.

The inlet 26 of the turbine I1 is connected to the compressed air outletI2 of the heat ex changer III, and the outlet 21 of the turbine I1 isconnected through duct means 28 with the interior of the cabin, cockpit.or compartment 29. The compressed air inlet II is connected to acompressor 30 or other source of air under pressure which may be of anyknown type. In the operation of the device shown n Fig. i, thecompressed air which is to be delivered to the cabin is received inheated state, due to its compression, by the heat exchanger I and isinitially cooled as it travels through the compressed air passagesthereof to the inlet of the turbine I1. The compressed air then passesthrough the operative mechanism of theturbine I1`to drive the rotor I8so that the impeller 24 of the suction pump 22 will be driven. Theabsorption 4` of power from the air resulting from the driving of theturbine rotor I8, results in a further cooling of the compressed air.

The coolant air, taken into the aircraft by a ram or scoop I3 facinginto the relative wind and conducted as by ducting I' and vI5, passesinto the coolant inlet I3 and is carried through the operative parts ofthe turbine 2I which abstracts heat energy from the coolant air, thisresulting in a cooling of the air and a recovery of power which istransmitted through the shaft I! to the impeller 24 to assist in drivingit. In addition to the cooling of the air by the turbine 2|, the coolantair has its heat content lowered as a result of the reduction inpressure caused by the suction of the impeller 24. In the form of theinvention shown in Fig. 1, coolant air outlet 25 is connected to theambient atmosphere, as by ducting (not shown).

In the form of the invention shown in Fig. 2, the outow air of an airconditioned or pressurized cabin is employed as the coolant air in asystem of the general character shown inFlg. 1.

vIn Fig. 2 I have shown a heat exchanger Ica of the general character ofthe heat exchanger I0, but of reduced size, located in a portion of apressurized cabin 29a. With the exception that the coolant air inlet I3receives air from the cabin, the coolant air outlet i4 is connectedthrough the suction pump 22 with a duct 35 leading to the exterior ofthe cabin 29a, and the outlet 21 of the turbine I1 is connected to anair distributing duct 36 in the cabin 29a, the mechanism of Fig. 1 hasbeen employed and the same numerals are employed in Fig. 2 to identifythe previously described parts therein. A primary ambient air cooler I1is disposed between the air compressing means 3p and the inlet II oi theheat exchanger IIIa. As shown in Fig. 2. this cooler or heat exchanger31 may be placed outside the cabin 29a so that ambient air will passthrough its coolant air passages and perform a primary cooling of thecompressed air which moves through the compressed air passages of theheat exchanger 31 to the heat exchanger IIIa, wherein the compressed airis further cooled lby heat exchange with coolant .air received from thecabin 28a.

When air is permitted to escape from a pressurized cabin into theambient atmosphere through ordinary outflow valves or ports, the powerrepresented by the compression of the air is wasted. In my presentinvention a reasonable proportion of this power of compression in thecabin air is recovered by the turbine 2| through which the air is passedon its way to the outflow duct 25.

Among the important features of the invention is the placement of thework extraction engine 2| in the path of the flow of the compressiblecoolant in such a position that it will act thereon before the coolantflows over the heat exchange walls-for example, the surfaces of thetubes IIIa of the cooling means I0, so that the temperature of thecoolant is reduced before it acts in its heat absorbing capacity, and afurther feature ofthe invention is to transmit power recovered by theextraction of work from the coolant by the engine 2| to 'a suctionmeans, shown as the suction pump or blower 22, in the path of flow ofthe coolant after it has passed over the heat exchange walls of thecooling means I0, to assist the flow of the coolant therethrough.

In the form of the invention shown in Fig. 3, the system for coolingcompressed air which is to be delivered to the pressurized cabin is thesame as that shown in Fig. 2, and consists of compressing the air in theair compressing means 30, cooling it as it travels through the primaryambient air cooler 21 and the secondary cooler Ib to the inlet 28 of theturbine I1, passing it through the operative mechanism of the turbine I1to further cool it, and passing it through a divided duct 4|! into ducts4I and 42 as indicated by arrows 43 and 44. The ducts 42 communicates atits rightward end with the distribution duct 36h which is connected withthe cabin 29h and the air outlet duct 45 of the cabin communicates withtheleftward end of the duct 4I. The primary ambient air cooler 31 isplaced outside the cabin 29h so that ambient air may be passed throughits coolant air passages and perform a primary cooling of the compressedair which moves through the compressed air passages of the cooler.

Power recovered by the turbines I1 and 2i drives a recirculation fan orblower having an impeller 46 mounted on the rightward end of the 7sshaft I9 which carries the rotors of the turbines l1 and 2|. Theimpeller 46 recirculates some of the air from the duct Il through theduct 42, the duct 36h, the cabin 29h, and the duct 45 to the duct 4Iwhich communicates with the inlet of the turbine 2l so that a volume ofair substantially equal to the volume of air which enters through theturbine I1 is passed through the turbine 2i, the duct I 3 and thecoolant Vair spaces of the heat exchanger lob to the coolant air outlet39 which communicates' with ambient atmosphere. Other work absorbingmeans which may be utilized in place of the cabin air recirculating fan46 are electrical generator, oil pump, fuel pump, vacuum pump, etc.

Herein the term compressed air is used to refer to the air which isplaced under sufflcient pressure to cause its movement through thesystem into the cabin or other space which is to be air-conditioned.This pressure or compression will vary in accordance with the pressurewhich is to be maintained in the air-conditioned space.

I claim as my invention:

l. Mechanism for conditioning air for the cabin of an aircraft having acompressor, comprising: a cooler having passages for the ilowtherethrough of compressed air from said compressor and having an inletand an outlet for said passages, said cooler having interspaces for theow of coolant air in heat exchange relation to said passages, means fordelivering compressed air from said compressor to said inlet, a turbinein said outlet for abstracting heat energy from the compressed airpassing therethrough and thereby further cooling the compressed airafter the initial cooling in said passages, said cooler having for saidinterspaces thereof an inlet and an outlet for the coolant air axiallyaligned with each other and with said turbine, and means including a fanreceiving driving power from said turbine for circulating coolant airthrough said interspaces, said fan comprising a suction fan disposed insaid coolant outlet, a heat energy absorbing turbine in said coolantinlet, and a common shaft on which both of said turbines and said fanare mounted.

2. In a cooling device provided with a heat exchanger having heattransfer walls and with means for conducting a ow of compressible fluidcoolant thereover, work extraction means preceding said heat exchangerand driven by said ow of coolant, and means disposed in the dischargeflow of coolant from said heat exchanger for assisting the flowtherethrough, said llast named means being driven by said workextraction means.

3. Mechanism for conditioning air for the cabin of an aircraft having acompressor, comprising: a cooler having passages for the ow therethroughof compressed air from said compressor and having an inlet and an outletfor said pas-- sages, said cooler having interspaces for the ilow ofcoolant air in heat exchange relation to said passages, means fordelivering compressed air from said compressor to said inlet. a turbinein said outlet for abstracting heat energy from the compressed airpassing therethrough and thereby further cooling the compressed airafter the inltial cooling in said passages, said cooler having for saidinterspaces a coolant inlet and a coolant outlet for the coolant airaxially aligned with each other and with said turbine, said coolantinlet being connected to the cabin interior and said coolant outletbeing connected to the outer atmosphere, and means including a fanreceiving driving power from said turbine for circulating coolant airthrough said interspaces, said fan comprising a suction fan disposed insaid coolant outlet, a heat energy absorbing turbine in said coolantinlet, and a common shaft on which both of said turbines and said fanare mounted.

4. In mechanism for conditioning air delivered from a compressing meansto a cabin and recirculating the cabin air, the combination of: a heatexchanger having an inlet and an outlet for compressed air, and an inletand an outlet for coolant air; means for connecting the compressed airinlet to said compressing means; a cooling and power recovery turbineconnected to said compressed air outlet; air pumping means forrecirculating the cabin air; and a drive connection between said turbineand said air pumping means.

5. In mechanism for conditioning air delivered from a compressing meansto a cabin and recirculating the cabin air, the combination of a heatexchanger having an inlet and an outlet for compressed air, and an inletand an outlet for coolant air, said coolant inlet being connected tosaid cabin; means for connecting the compressed air inlet to saidcompressing means; means for connecting said compressed air outlet tosaid cabin; a cooling and power recovery turair through said heatexchanger from said coolant inlet to said coolant outlet thereof; asecond cooling and power recovering turbine connected to said coolantair inlet; and a drive connection betweenat least one of said turbinesand said air pumping means.

7. In mechanism for conditioning air delivered from a. compressing meansto a cabin, the cornbination of a heat exchanger having an inlet and anoutlet for compressed air, and an inlet and an outlet for coolant air;means for connecting the compressed air inlet to said compressing means;a cooling and power recovery turbine connected to said compressed airoutlet; air pumping means connected to said coolant air outlet formoving air through the coolant passages of said heat exchanger bysuction; a second cooling and power recovery turbine connected to saidcoolant air inlet; and a drive connection between at least one of saidturbines and said air pumping means.

8. In mechanism for conditioning air delivered from a compressing meansto a cabin, the combination of a heat exchanger having an inlet and anoutlet for compressed air, and an inlet and an outlet for coolant air;means for directing air from the interior of said cabin to said coolantair inlet; air discharge means for connecting said coolant air outlet tothe outer atmosphere; means for connecting the compressed air inlet tosaid compressing means; a cooling and power recovery turbine connectedto said compressed air outlet; air pumping means for producing a ilow ofcoolant air through said heat exchanger from said coolant inlet to saidcoolant outlet thereof; and a drive connection between said turbine andsaid air pumping means.

9. In mechanism for conditioning air delivered from a compressing meansto a cabin, the combination of: a heat exchanger having an inlet Y andan outlet for compressed air, and an inlet and an outlet for coolantair; means for directing air from the interior of said cabin to saidcoolant air inlet; air discharge means for connecting said coolant airoutlet .to the outer atmosphere; means for connecting the compressed airinletto said compressing means; a cooling and power recovery turbineconnected to said compressed air outlet; air pumping means connected tosaid coolant air outlet for moving air through the coolant passages ofsaid heat exchanger by suction; and a drive connection between saidturbine and said air pumping means.

10. In mechanism for conditioning air delivered from a compressing meansto a cabin, the combination of: a heat exchanger having an inlet and anoutlet for compressed air, and an inlet and an outlet for coolant air;means ior connecting the compressed air inlet to said compressing means;a cooling and power recovery turbine connected to said compressed airoutlet; air pumping means connected to said coolant air outlet formoving air through the coolant passages of said heat exchanger bysuction; a second cooling and power recovery turbine connected to saidcoolant air inlet; means ior delivering air from the interior of saidcabin to said second turbine; air discharge means for connecting saidcoolant air outlet to the outer atmosphere; and a drive connectionbetween at least one of said I turbines and said air pumping means.

11. In mechanism for conditioning air delivered from a compressing meansto a cabin, the combination of: a heat exchanger having an inlet and anoutlet for compressed air, and an inlet and an outlet for coolant air;means for connecting the compressed air inlet to said comand an outletfor compressed air, and an inlet` and an outlet for coolant air; meansfor connecting the compressed air inlet to said compressing means; acooling and power recovery turbine connected to said compressed airoutlet; 4a second cooling and power recovery turbine connected to saidcoolant air inlet; means for delivering air from the interior of saidcabin `to said second turbine; air discharge means for connecting saidcoolant air outlet to the outer atmosphere; and

means for utilizing the power recovered by said',

turbines.

13. In mechanism for conditioning Vair for the interior to the inlet oi'said turbine; means for connecting the outlet of said air pumping meansto the outer atmosphere; and a drive connection between said turbine andsaid air pumping means.

ifi. In cooling air which is to be delivered into a cabin by use of aheat exchanger having a compressed air passage means and coolant airpassage means, air pumping means and a cooling and power recoveryturbine, a method comprising the steps of: compressing air and passingit through the compressed air passage means oi' said heat exchanger andthrough said turbine to said cabin; and utilizing power recovered bysaid turbine to recirculate air through a closed circuit which includessaid cabin.

15. In cooling air which is to be delivered into a cabin by use of aheat exchanger having a. compressed air passage means and coolant airpas sage means, air pumping means and first and second cooling and powerrecovery turbines, a method comprising the steps of: compressing air andpassing it through the compressed air passage means oi.' said heatexchanger and through `said iirst turbine to said cabin; establishing apath of flow of coolant air through said second turbine and said coolantair passage means of said heat exchanger; and utilizing power recoveredby at least one oi said turbines to pump coolant air through saidcoolant air passage means.

16. In cooling air which is to be delivered into a cabin by use of aheat exchanger having a compressed air passage means and coolant airpassage means, air pumping means and rst and second cooling and powerrecovery turbines, a method comprising the steps of compressing air andpassing it through the compressed air passage means of saidheatexchanger and through said iirst turbine to said cabin; establishing apath of flow of coolant air through said second turbine and said coolantair passage means of said heat exchanger; and utilizing power recoveredby at least one of said turbines to pump coolant 'air through saidcoolant air passage means by suction effect applied to the outlet ofsaid coolant air passage means.

17. In cooling air which is tor be delivered into a cabin by use of aheat exchanger having a compressed air passage means and coolant airpassage means, air pumping means and rst and second cooling and powerrecovery turbines, a method comprising the steps of: compressing air andpassing it through the compressed air passage means of said heatexchanger and through said first turbine to said cabin; establishing apath of iiow of coolant air through said second turbine and saidcoolant. air passage means of said heat exchanger; utilizing the powerrecovered by said turbines: and applying suction eiect tothe outletofsaid coolant airv passage means of said heat exchanger to move coolantair .therethrough. f I

18. In cooling air which is tobe delivered into a cabin by use of aheat'exchangerhaving a compressed air passage means andY coolant vairpassage means. air pumping means andnrst and second cooling and powerrecovery turbines, a method comprising the steps of: compressing air andpassing it through the compressed air passage means oi said heatexchanger and through said first turbine to said cabin; establishing apath of ilow of coolant air from the cabin interior through said secondturbine and said coolant air passage means of said heat exchanger to theouter atmosphere; and utilizing power recovered by at least one of saidturbines to pump coolant air through said coolant air passage means.

19. In an aircraft cooling means provided with a heat exchanger: meansdening independent airilow paths connected to said heat a source ofcoolant air under ram pressure con.

nected to one of said paths; and means for precooling said coolant aircomprising work extraction means preceding said heat exchanger anddriven by said coolant airflow.

21. In an aircraft cooling means provided with a heat exchanger: meansdefining independent airilow paths connected to said heat exchanger: asource of compressed coolant air connected to one of said paths; andmeans for pre-cooling said coolant air comprising work extraction meanspreceding said heat exchanger and driven by said coolant airflow.

22. In mechanism for conditioning compressed air delivered to a cabin,the combination of: a heat exchanger having an inlet and an outlet forcompressed air, and an inlet and an outlet for coolant air; means forconnecting the compressed air inlet with a source of compressed air;means for connecting the coolant air inlet with a source of air atatmospheric pressure; a cooling and power recovery turbine connected tosaid compressed air outlet; air pumping means driven by said turbine forproducing a pressure differential between the coolant inlet and outlet;and a second cooling and power recovery turbine connected to saidcoolant inlet having a driving connection with said rst turbine.

23. In mechanism for conditioning compressed air delivered to a cabin,the combination oi': a heat exchanger having an inlet and an outlet forcompressed air, and an inlet and an outlet for coolant air; means forconnecting the compressed air inlet with a source of compressed air;means for connecting the coolant air inlet with a source of air underram pressure; a cooling and power recovery turbine connected to saidcoolant inlet; air pumping means driven by said turbine for augmentingow of coolant air between the coolant inlet and outlet; and workextraction means connected to said compressed air outlet and driven bythe compressed air for further cooling it prior to delivery to thecabin.

24. In mechanism for conditioning compressed air delivered to a cabin,the combination of: a heat exchanger having an inlet and an outlet forcompressed air, and an inlet and an outlet for coolant air; means forconnecting the compressed air inlet with a source of compressed air; aircompressing means connected with the coolant air inlet; a cooling andpower recovery turbine connected between said compressing means andcoolant inlet; air pumping means driven by said turbine for augmentingilow of coolant air between the coolant inlet and outlet; and workextraction means connected to said compressed air outlet and driven bythe compressed air for further cooling it prior to delivery to thecabin.

loA

25. A system for cooling the air within an aircraft compartment,comprising: a ram inlet: means for converting energy of said ram airinto mechanical energy; heat exchanging means receiving the air cooledby said last named means; a compressor for increasing the flow of airinto said inlet; means for transmitting said mechanical energy to saidcompressor to drive the same; and duct means leading from the atmospherethrough said heat exchanging means to said compartment.

26. The method of reducing the temperature of air supplied to acompartment of an aircraft comprising the steps of extracting energyfrom ram air by substantially adiabatically expanding said air to lowerthe temperature thereof; passing said expanded .air through a heatexchanging means in heat receiving relationship with ventilation airprior to its introduction into said compartment; and utilizing theenergy extracted from said ram air to increase the expansion of said ramair.

27. The method of reducing the temperature of air supplied to acompartment of an aircraft comprising the steps of: extracting energyfrom ram air by substantially adiabatically expanding said air bypassing the same through an expansion turbine to lower the temperatureof said air; passing said expanded air through a heat exchanging meansin heat receiving relationship with ventilation air to be supplied tosaid compartment; introducing said cooled ventilation air to saidcompartment; and driving an air moving means by the energy extractedfrom said air to increase the rate of flow oi' air through said turbine.

28. A system for cooling the air for delivery to a compartment,comprising: a coolant air duct; a turbine arranged in said coolant airduct; a

heat exchanger through which the air cooled by' expansion through theturbine is directed; compressor means adapted to be driven by saidturbine forV increasing the flow of air through said turbine; means forleading a flow of air through said heat exchanger to be cooled thereby;and means for conducting the air cooled by passage through said heatexchanger to said compartment.

29. A system for cooling the air for delivery to a compartment,comprising: a source of compressed air; turbine means for expanding saidair to reduce the temperature thereof; means for conducting air to saidcompartment; heat exchanging means mounted in said conducting meansthrough which air cooled by said expansion passes to thereby reduce thetemperature of the air conducted to said compartment: and means drivenby said turbine means for increasing the rate of flow of air throughsaid turbine means.

30. A system for cooling the air within an aircraft compartment,comprising: a ram inlet; a duct for receiving ram air from said inlet; aturbine arranged in said duct; a heat exchanger carried by said ductthrough which the air cooled by expansion through the turbine isdirected; compressor means mounted in said duct downstream from saidheat exchanger for augmenting the flow of air through said duct; meansfor leading air through said heat exchanger in heat exchangingrelationship with the air cooled by expansion through said turbine; andconduit means for leading the cooled air from said heat exchanger tosaid compartment.

aircraft compartment, comprising: a ram inlet;

duct means leading from said inlet to the atmosphere; a turbine arrangedin said duct means;

compressor means mounted in-said d uct means 5 adapted to be driven bysaid turbine to increase the ow of air therethrough; a heat exchangerdisposed in said duct means intermediate said turbine and compressorthrough which'the air cooled by expansion through'the turbine isdirected; means for leading air through said heat exchanger; and conduitmeans leading from said heat exchanger to said compartment.

WALDEMAR F. MAYEB.

12 REFERENCES cn'm The following references are'V of record in the 111eoi' this patent:

Mayo Nov. 16. 1948

